37° Flare (JIC) Fittings
37° Flare (JIC) Union
Straight 37° flare (JIC) union for connecting two tubes of the same outside diameter using 37° flared connections. Available in a wide range of sizes for hydraulic and industrial fluid systems.
Specifications
- Series
- JU Series
- Connection
- 37° Flare Tube × 37° Flare Tube
- Flare Angle
- 37°
- Tube O.D.
- 1/8 to 2 in.; metric tube O.D. options available by configuration
- Configuration
- Straight Equal Union
- Standard Basis
- SAE J514 / ISO 8434-2
- Standard Material
- 316 Stainless Steel
Overview
The JU Series 37° Flare Union provides a straight connection between two flared tubes of the same outside diameter.
Each end uses a 37° flare interface. Tightening the fitting nut clamps the tube flare against the fitting seat, creating a metal-to-metal sealing interface between the mating 37° surfaces.
The straight equal-union configuration is used where two tube sections need to be joined inline without changing tube size or introducing a pipe-thread port connection.
Key Features
- Straight tube-to-tube connection
- Equal-size 37° flare connections at both ends
- Metal-to-metal sealing at the mating 37° flare surfaces
- Wide range of tube O.D. options
- Detachable connection for tube-system assembly and maintenance
- 316 stainless steel as the standard material
- Based on the SAE J514 / ISO 8434-2 37° flare fitting system
Engineering Specifications
Parameter | Specification |
|---|---|
Fitting Type | Union |
Connection | 37° Flare Tube × 37° Flare Tube |
Flare Angle | 37° |
Configuration | Straight Equal Union |
Tube O.D. Range | 1/8 to 2 in.; metric options depending on configuration |
Standard Basis | SAE J514 / ISO 8434-2 |
Standard Material | 316 Stainless Steel |
Tube Size Options
JU Series 37° Flare Unions are available for a wide range of tube sizes. Each union connects two tubes of the same outside diameter.
Common fractional configurations include:
Tube O.D. | 37° Flare Thread |
|---|---|
1/8 in. | 5/16-24 |
3/16 in. | 3/8-24 |
1/4 in. | 7/16-20 |
5/16 in. | 1/2-20 |
3/8 in. | 9/16-18 |
1/2 in. | 3/4-16 |
5/8 in. | 7/8-14 |
3/4 in. | 1 1/16-12 |
7/8 in. | 1 3/16-12 |
1 in. | 1 5/16-12 |
1 1/4 in. | 1 5/8-12 |
1 1/2 in. | 1 7/8-12 |
2 in. | 2 1/2-12 |
Available dimensions and configurations vary by tube O.D.
Sealing Principle
The 37° flare connection seals between the fitting seat and the inside surface of the properly prepared tube flare.
The fitting threads and nut provide the clamping force that holds the mating 37° surfaces together. The threads themselves are not the primary sealing surface.
Tube flares and fitting seats should be clean and free from scratches, cracks, burrs or other damage that could interfere with the sealing surfaces.
Working Pressure
Working pressure depends on fitting size, tube material, tube wall thickness, operating temperature and the complete assembly.
Representative working pressures for the 37° flare fitting system are:
Tube O.D. / SAE Size | Working Pressure |
|---|---|
1/8 to 3/8 in. / -2 to -6 | Up to 5000 psi / 345 bar |
1/2 in. / -8 | Up to 4500 psi / 310 bar |
5/8 to 3/4 in. / -10 to -12 | Up to 3500 psi / 241 bar |
7/8 to 1 in. / -14 to -16 | Up to 3000 psi / 207 bar |
1 1/4 in. / -20 | Up to 2500 psi / 172 bar |
1 1/2 in. / -24 | Up to 2000 psi / 138 bar |
2 in. / -32 | Up to 1500 psi / 103 bar |
Pressure capability of the complete assembly is limited by the lowest-rated component. Tube material, wall thickness and operating conditions should therefore be considered when selecting the fitting.
Material
Standard Material: 316 Stainless Steel
316 stainless steel is used for corrosion resistance and mechanical performance in hydraulic and industrial fluid systems.
Material requirements should be specified with the application, fluid medium and operating conditions when requesting a quotation.
Typical Applications
37° Flare (JIC) Union Fittings are commonly used in:
- Hydraulic power units
- Industrial machinery
- Mobile hydraulic equipment
- Machine tools
- Pumps and hydraulic control systems
- Test equipment
- Process and utility equipment
- Hydraulic tube installations requiring a straight tube-to-tube connection
Selection & Ordering Information
To specify the required 37° Flare (JIC) Union Fitting, provide:
- Tube O.D.
- Material
- Tube material and wall thickness
- Operating pressure and temperature
- Fluid or process medium
- Quantity
Existing part numbers, drawings, BOMs or product references can also be provided for product matching and quotation review.
